Application multi-versioning in a traditional language environment

ABSTRACT

Operating an online transaction processing system to perform an application including a first module call by performing the following steps (not necessarily in the following order): (i) assigning a dedicated search path to the application, where the search path specifies an ordered set of location(s) for searching for module code, the set of location(s) includes at least a first dynamic module library and the first dynamic module library is ahead of any other locations which may be included in the dedicated search path; (ii) running the application through the transaction processing system; (iii) receiving the first module call, from the running of the application, specifying a requested module using a requested module name; and (iv) in response to the module call, locating the requested module based on the requested module name and the dedicated search path.

STATEMENT ON PRIOR DISCLOSURES BY AN INVENTOR

The following disclosure(s) are submitted under 35 U.S.C. 102(b)(1)(A)as prior disclosures by, or on behalf of, a sole inventor of the presentapplication or a joint inventor of the present application:

(i) “The IBM CICS Transaction Server for z/OS, V5.2 open beta offeringtakes service agility, operational efficiency, and cloud enablement to anew level”, IBM United States Software announcement, 214-015, dated Jan.21, 2014, pp. 1-14.

BACKGROUND OF THE INVENTION

The present invention relates generally to the field of applicationhosting, and more particularly to application hosting where there aremultiple versions of the applications.

One conventional piece of software used in application hosting is calledCustomer Information Control System (CICS). CICS is a transaction serverthat runs primarily on certain conventional mainframe computer systems.CICS is middleware designed to support rapid, high-volume onlinetransaction processing. A CICS transaction is a unit of processinginitiated by a single request that may affect one or more objects. Thisprocessing may be interactive (screen-oriented), or may occur asbackground transactions. CICS provides services that extend and/orreplace functions of an operating system and can be more efficient andsimpler than using the generalized services in the operating system,especially in connection with communication with diverse terminaldevices.

Applications developed for CICS have been written in a variety ofprogramming languages and use CICS-supplied language extensions to: (i)interact with resources such as files, database connections andterminals, or (ii) to invoke functions such as web services. CICS iscurrently used by clients such as financial institutions, largecommercial enterprises, smaller organizations and government entities.Customers have a huge investment in home-grown or highly customizedpackaged applications written in traditional languages such as COBOL(common business oriented language), PL/I (programming language one), C,and ASM (assembly language). These applications, when hosted on amiddleware platform like CICS, include many, possibly thousands, ofindividual uniquely named program modules. Duplicate program modulenames are not permitted which means it is impossible to: (i) host morethan one version of an application (where there are common module nameswhich are common to both versions of the application); and/or (ii) hosttwo different applications that have inadvertently chosen the samemodule names.

In some middleware transaction servers (for example, pre-5.2 versions ofCICS), there is only a single directory for module names. In theseconventional transaction servers, when a program issued an “EXEC CICSLINK” command (that is, a module call), the target module name waslooked up and called if found. If not found in an initial look-up (thatis, a look-up in an in-memory cache), then the conventional transactionserver will search a “global search path” by searching the followinglocations in the following order: (i) LPA (link pack area); (ii) dynamiclibraries; and (iii) RPL (relocatable program library). Theseconventional transaction servers then load the first matching module.

The role of dynamic libraries in an application server, implemented by aconventional transaction server, will now be discussed. The primarypurpose of a dynamic library, in currently conventional CICS systems, isto allow new datasets to be added to those defined by a data set that isnamed DFHRPL in the CICS context. However, DFHRPL cannot be modifiedwithout restarting CICS. Additionally, if the datasets are defined witha higher ranking than those in DFHRPL programs already loaded can bereplaced by newer versions if the SET PROGRAM NEWCOPY or PHASEIN commandis used. This mechanism does not allow two or more versions of a programto be explicitly used simultaneously.

SUMMARY

According to an aspect of the present invention, there is a method,computer program product and/or system for operating an onlinetransaction processing system to perform an application including afirst module call. The method, system and/or product perform thefollowing steps (not necessarily in the following order): (i) assigninga dedicated search path to the application, where the search pathspecifies an ordered set of location(s) for searching for module code,the set of location(s) includes at least a first dynamic module libraryand the first dynamic module library is ahead of any other locationswhich may be included in the dedicated search path; (ii) running theapplication through the transaction processing system; (iii) receivingthe first module call, from the running of the application, specifying arequested module using a requested module name; and (iv) in response tothe module call, locating the requested module based on the requestedmodule name and the dedicated search path.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram view of a first embodiment of an applicationserver system according to the present invention;

FIG. 2 is a flowchart showing a first embodiment method performed, atleast in part, by the first embodiment system;

FIG. 3 is a block diagram view of a machine logic (for example,software) portion of the first embodiment system; and

FIG. 4 is another block diagram view of a machine logic (for example,software) portion of the first embodiment system.

DETAILED DESCRIPTION

In some embodiments of the present invention, an online TP (transactionprocessing) system uses a “dynamic library” (which lists one or moredatasets from which modules are loaded). The dynamic library is added toa private search path unique to each application or version of anapplication. Using the private search path and its referenced dynamiclibrary, an application can define and load modules with the same name(that is, duplicate module names can be used in different applications)as long as the modules are located in different datasets. Morespecifically, in some embodiments, the private search path is searchedbefore searching the global search path so that the dynamic library willbe used to find modules (at least in the first instance), rather thanthe global search path. In this way, multiple versions of an applicationcan be hosted on the same TP platform without modifying module names orrelying on naming indirection. This Detailed Description section isdivided into the following sub-sections: (i) The Hardware and SoftwareEnvironment; (ii) Example Embodiment; (iii) Further Comments and/orEmbodiments; and (iv) Definitions.

I. The Hardware and Software Environment

The present invention may be a system, a method, and/or a computerprogram product. The computer program product may include a computerreadable storage medium (or media) having computer readable programinstructions thereon for causing a processor to carry out aspects of thepresent invention.

The computer readable storage medium can be a tangible device that canretain and store instructions for use by an instruction executiondevice. The computer readable storage medium may be, for example, but isnot limited to, an electronic storage device, a magnetic storage device,an optical storage device, an electromagnetic storage device, asemiconductor storage device, or any suitable combination of theforegoing. A non-exhaustive list of more specific examples of thecomputer readable storage medium includes the following: a portablecomputer diskette, a hard disk, a random access memory (RAM), aread-only memory (ROM), an erasable programmable read-only memory (EPROMor Flash memory), a static random access memory (SRAM), a portablecompact disc read-only memory (CD-ROM), a digital versatile disk (DVD),a memory stick, a floppy disk, a mechanically encoded device such aspunch-cards or raised structures in a groove having instructionsrecorded thereon, and any suitable combination of the foregoing. Acomputer readable storage medium, as used herein, is not to be construedas being transitory signals per se, such as radio waves or other freelypropagating electromagnetic waves, electromagnetic waves propagatingthrough a waveguide or other transmission media (e.g., light pulsespassing through a fiber-optic cable), or electrical signals transmittedthrough a wire.

Computer readable program instructions described herein can bedownloaded to respective computing/processing devices from a computerreadable storage medium or to an external computer or external storagedevice via a network, for example, the Internet, a local area network, awide area network and/or a wireless network. The network may comprisecopper transmission cables, optical transmission fibers, wirelesstransmission, routers, firewalls, switches, gateway computers and/oredge servers. A network adapter card or network interface in eachcomputing/processing device receives computer readable programinstructions from the network and forwards the computer readable programinstructions for storage in a computer readable storage medium withinthe respective computing/processing device.

Computer readable program instructions for carrying out operations ofthe present invention may be assembler instructions,instruction-set-architecture (ISA) instructions, machine instructions,machine dependent instructions, microcode, firmware instructions,state-setting data, or either source code or object code written in anycombination of one or more programming languages, including an objectoriented programming language such as Smalltalk, C++ or the like, andconventional procedural programming languages, such as the “C”programming language or similar programming languages. The computerreadable program instructions may execute entirely on the user'scomputer, partly on the user's computer, as a stand-alone softwarepackage, partly on the user's computer and partly on a remote computeror entirely on the remote computer or server. In the latter scenario,the remote computer may be connected to the user's computer through anytype of network, including a local area network (LAN) or a wide areanetwork (WAN), or the connection may be made to an external computer(for example, through the Internet using an Internet Service Provider).In some embodiments, electronic circuitry including, for example,programmable logic circuitry, field-programmable gate arrays (FPGA), orprogrammable logic arrays (PLA) may execute the computer readableprogram instructions by utilizing state information of the computerreadable program instructions to personalize the electronic circuitry,in order to perform aspects of the present invention.

Aspects of the present invention are described herein with reference toflowchart illustrations and/or block diagrams of methods, apparatus(systems), and computer program products according to embodiments of theinvention. It will be understood that each block of the flowchartillustrations and/or block diagrams, and combinations of blocks in theflowchart illustrations and/or block diagrams, can be implemented bycomputer readable program instructions.

These computer readable program instructions may be provided to aprocessor of a general purpose computer, special purpose computer, orother programmable data processing apparatus to produce a machine, suchthat the instructions, which execute via the processor of the computeror other programmable data processing apparatus, create means forimplementing the functions/acts specified in the flowchart and/or blockdiagram block or blocks. These computer readable program instructionsmay also be stored in a computer readable storage medium that can directa computer, a programmable data processing apparatus, and/or otherdevices to function in a particular manner, such that the computerreadable storage medium having instructions stored therein comprises anarticle of manufacture including instructions which implement aspects ofthe function/act specified in the flowchart and/or block diagram blockor blocks.

The computer readable program instructions may also be loaded onto acomputer, other programmable data processing apparatus, or other deviceto cause a series of operational steps to be performed on the computer,other programmable apparatus or other device to produce a computerimplemented process, such that the instructions which execute on thecomputer, other programmable apparatus, or other device implement thefunctions/acts specified in the flowchart and/or block diagram block orblocks.

The flowchart and block diagrams in the Figures illustrate thearchitecture, functionality, and operation of possible implementationsof systems, methods, and computer program products according to variousembodiments of the present invention. In this regard, each block in theflowchart or block diagrams may represent a module, segment, or portionof instructions, which comprises one or more executable instructions forimplementing the specified logical function(s). In some alternativeimplementations, the functions noted in the block may occur out of theorder noted in the figures. For example, two blocks shown in successionmay, in fact, be executed substantially concurrently, or the blocks maysometimes be executed in the reverse order, depending upon thefunctionality involved. It will also be noted that each block of theblock diagrams and/or flowchart illustration, and combinations of blocksin the block diagrams and/or flowchart illustration, can be implementedby special purpose hardware-based systems that perform the specifiedfunctions or acts or carry out combinations of special purpose hardwareand computer instructions.

An embodiment of a possible hardware and software environment forsoftware and/or methods according to the present invention will now bedescribed in detail with reference to the Figures. FIG. 1 is afunctional block diagram illustrating various portions of applicationserver system 100, including: transaction sub-system 102; clientsub-systems 104, 106, 108, 110, 112; communication network 114;transaction server computer 200; communication unit 202; processor set204; input/output (I/O) interface set 206; memory device 208; persistentstorage device 210; display device 212; external device set 214; randomaccess memory (RAM) devices 230; cache memory device 232; andtransaction server software 300. In this embodiment: (i) the applicationserver system serves applications to clients 104, 106, 108, 110, 112;(ii) the transaction server is hosted on a single physical computer (inother embodiments it may be spread among and between multiple physicaland/or virtual machines); and (iii) transaction server software 300 is,or includes, middleware.

Sub-system 102 is, in many respects, representative of the variouscomputer sub-system(s) in the present invention. Accordingly, severalportions of sub-system 102 will now be discussed in the followingparagraphs.

Sub-system 102 may be a laptop computer, tablet computer, netbookcomputer, personal computer (PC), a desktop computer, a personal digitalassistant (PDA), a smart phone, or any programmable electronic devicecapable of communicating with the client sub-systems via network 114.Software 300 is a collection of machine readable instructions and/ordata that is used to create, manage and control certain softwarefunctions that will be discussed in detail, below, in the ExampleEmbodiment sub-section of this Detailed Description section.

Sub-system 102 is capable of communicating with other computersub-systems via network 114. Network 114 can be, for example, a localarea network (LAN), a wide area network (WAN) such as the Internet, or acombination of the two, and can include wired, wireless, or fiber opticconnections. In general, network 114 can be any combination ofconnections and protocols that will support communications betweenserver and client sub-systems.

Sub-system 102 is shown as a block diagram with many double arrows.These double arrows (no separate reference numerals) represent acommunications fabric, which provides communications between variouscomponents of sub-system 102. This communications fabric can beimplemented with any architecture designed for passing data and/orcontrol information between processors (such as microprocessors,communications and network processors, etc.), system memory, peripheraldevices, and any other hardware components within a system. For example,the communications fabric can be implemented, at least in part, with oneor more buses.

Memory 208 and persistent storage 210 are computer-readable storagemedia. In general, memory 208 can include any suitable volatile ornon-volatile computer-readable storage media. It is further noted that,now and/or in the near future: (i) external device(s) 214 may be able tosupply, some or all, memory for sub-system 102; and/or (ii) devicesexternal to sub-system 102 may be able to provide memory for sub-system102.

Software 300 is stored in persistent storage 210 for access and/orexecution by one or more of the respective computer processors 204,usually through one or more memories of memory 208. Persistent storage210: (i) is at least more persistent than a signal in transit; (ii)stores the program (including its soft logic and/or data), on a tangiblemedium (such as magnetic or optical domains); and (iii) is substantiallyless persistent than permanent storage. Alternatively, data storage maybe more persistent and/or permanent than the type of storage provided bypersistent storage 210.

Software 300 may include both machine readable and performableinstructions and/or substantive data (that is, the type of data storedin a database). In this particular embodiment, persistent storage 210includes a magnetic hard disk drive. To name some possible variations,persistent storage 210 may include a solid state hard drive, asemiconductor storage device, read-only memory (ROM), erasableprogrammable read-only memory (EPROM), flash memory, or any othercomputer-readable storage media that is capable of storing programinstructions or digital information.

The media used by persistent storage 210 may also be removable. Forexample, a removable hard drive may be used for persistent storage 210.Other examples include optical and magnetic disks, thumb drives, andsmart cards that are inserted into a drive for transfer onto anothercomputer-readable storage medium that is also part of persistent storage210.

Communications unit 202, in these examples, provides for communicationswith other data processing systems or devices external to sub-system102. In these examples, communications unit 202 includes one or morenetwork interface cards. Communications unit 202 may providecommunications through the use of either or both physical and wirelesscommunications links. Any software modules discussed herein may bedownloaded to a persistent storage device (such as persistent storagedevice 210) through a communications unit (such as communications unit202).

I/O interface set 206 allows for input and output of data with otherdevices that may be connected locally in data communication with servercomputer 200. For example, I/O interface set 206 provides a connectionto external device set 214. External device set 214 will typicallyinclude devices such as a keyboard, keypad, a touch screen, and/or someother suitable input device. External device set 214 can also includeportable computer-readable storage media such as, for example, thumbdrives, portable optical or magnetic disks, and memory cards. Softwareand data used to practice embodiments of the present invention, forexample, program 300, can be stored on such portable computer-readablestorage media. In these embodiments the relevant software may (or maynot) be loaded, in whole or in part, onto persistent storage device 210via I/O interface set 206. I/O interface set 206 also connects in datacommunication with display device 212.

Display device 212 provides a mechanism to display data to a user andmay be, for example, a computer monitor or a smart phone display screen.

The programs described herein are identified based upon the applicationfor which they are implemented in a specific embodiment of theinvention. However, it should be appreciated that any particular programnomenclature herein is used merely for convenience, and thus theinvention should not be limited to use solely in any specificapplication identified and/or implied by such nomenclature.

The descriptions of the various embodiments of the present inventionhave been presented for purposes of illustration, but are not intendedto be exhaustive or limited to the embodiments disclosed. Manymodifications and variations will be apparent to those of ordinary skillin the art without departing from the scope and spirit of the invention.The terminology used herein was chosen to best explain the principles ofthe embodiment, the practical application or technical improvement overtechnologies found in the marketplace, or to enable others of ordinaryskill in the art to understand the embodiments disclosed herein.

II. Example Embodiment

FIG. 2 shows flowchart 250 depicting a method according to the presentinvention. FIGS. 3 and 4 shows software 300 (and constituent portionsthereof) for performing at least some of the method steps of flowchart250. This method and associated software will now be discussed, over thecourse of the following paragraphs, with extensive reference to FIG. 2(for the method step blocks) and FIGS. 3 and 4 (for the softwareblocks).

Processing begins at step S255, where application (“app”) call handler380 of transaction server software 300 receives an application call fromclient sub-system 104 (see FIG. 1) to run an application called “secondapplication,” which is denominated as second app 304 in FIG. 3. Thisapplication call of step S255 is made in a manner that is currentlyconventional for calling applications from an application server,implemented as a middleware transaction server, and will not bediscussed in detail here.

Processing proceeds to step S260, where processor(s) in applicationserver system 100 (for example, processor set 204) begin running theapplication code for second app 304 pursuant to the application callpreviously received at step S255. As part of running the applicationcode, code for the search path 312 is used to set up the way in whichmodule calls will be handled as the application continues to run. Inthis case, search path 312 of second app identifies the followinglocations to be searched, upon module calls, in the following order: (i)(i) second dynamic module library 326; (ii) first dynamic module library324; (iii) global module library 322; (iv) LPA (link pack area); and (v)RPL (relocatable program library). As the terms “dynamic library,” and“non-dynamic library,” are used in this document: (i) a “dynamic librarycan be modified without re-starting the transaction server; and (ii) a“non-dynamic library” cannot be modified without a restart of thetransaction server (DFHRPL in CICS is an example of a non-dynamiclibrary“).

Processing proceeds to step S265, where module call handler 390 receivesa module call from second application 304 as second application 304continues in its execution. More specifically, second app 304 calls amodule named “MOD_TWO.” In this embodiment, all of the modules for allof the applications, collectively, are stored in module library set 320of transaction server software 300 (see FIGS. 3 and 4). Morespecifically: (i) global module library includes modules named MOD_ONE331, MOD_TWO 332, MOD_THREE, MOD_FOUR, MOD_FIVE, MOD_SIX, MOD_SEVEN,MOD_EIGHT, MOD_NINE, and MOD_TEN 340; (ii) first dynamic module library324 includes modules named MOD_TWO 351 and MOD_ELEVEN 352; and (iii)second dynamic module library 326 includes a single module namedMOD_TWELVE 361.

As can be seen from the foregoing lists of the previous paragraph, thereare two modules named MOD_TWO, specifically: (i) MOD_TWO 332 of theglobal module library; and (ii) MOD_TWO 351. These are different modulesthat perform different functions, but they happen to have the same name.In conventional systems, this would be a problem, and (assuming theconventional system even allowed two different modules to be namedMOD_TWO), the wrong MOD_TWO might be run when second app 304 calls“MOD_TWO” at step S265. As will be discussed in connection with the nextstep of flowchart 250, this embodiment of the present invention preventsthis problem.

Processing proceeds to step S270, where module call handler 390 usessearch path 312 of second app 304 to determine the order in which thevarious libraries of module library set 320 will be searched for thecalled module “MOD_TWO.” As stated above, search path 312 specifies thatsecond dynamic module library 326 is to be the first location checkedwhen a module is called. In this embodiment, the second dynamic modulelibrary was created specifically for second app 304, and includesMOD_TWELVE 361, which is used in second app 304, and in no other.MOD_TWELVE 361 could have been placed, alternatively, or additionally inglobal module library 322 and/or first dynamic module library 324, but,in this example, the system designers chose to put MOD_TWELVE only inthe second dynamic module library (perhaps to avoid future nameconflicts in the global library).

However, MOD_TWELVE has not been called-rather, MOD_TWO has. Because nomodule named “MOD_TWO” is present in the library 326, the next libraryon search path 312 of second app 304 is next checked, specifically firstdynamic library 324. In this example: (i) second app 304 is a laterversion of first app 302 (which includes search path 311); (ii) firstapp 302 and second app 304 share much functionality and much code; (iii)first dynamic library 324 was originally created to store modules(especially name-conflicted modules) designed for use in first app 302;(iv) MOD_TWO (as it exists in first dynamic library 324) is aname-conflicted module that was originally designed for use with firstapp 302; and (v) MOD_ELEVEN 352 is a non-name-conflicted module that wasoriginally designed for use with first app 302. In this example, firstdynamic module library 324 is the second location on search path 312 ofsecond app 304 because second app 304 is closely related to first app302 that it is likely to (and indeed does) include modules needed toproperly run second app 304. Accordingly, module call handler locatesMOD_TWO 351, which is the correct MOD_TWO (unlike MOD_TWO 332 in globalmodule library 322), and causes MOD_TWO 351 to begin to be performedpursuant to the module call of step S265. Processing proceeds to stepS275, where performance of MOD_TWO 351 is completed.

This use of dynamic libraries is different than the conventional“indirection” process (described above in the Background section)because under at least some embodiments of the present invention, thisprocess is only used the first time a load module is called after whichit is cached in memory (that is, 232) and a directory used to map itsname to a pointer in that cache. Large applications comprising many loadmodules are typically loaded “lazily” to ensure a fast startup andreduce memory footprint. In this way, under some embodiments of thepresent invention, not every load module is required to satisfy eachclient request and a load module can: (i) remain on disk; or (ii) evenbe flushed from the cache if not used for a certain period of time orwhen memory becomes exhausted.

Processing proceeds to step S280, where control is returned to secondapp 304 (at least until further module calls are made by second app304). As a final note, it is noted that not every app will necessarilyhave its own dynamic module library. For example, third app 306 does nothave an associated dynamic module library, and, accordingly, its searchpath 313 specifies global module library 322 as its only library for itsmodule calls.

III. Further Comments and/or Embodiments

Some embodiments of the present invention recognize that applicationhosting environments where duplicate module names are not permitted canlead to troublesome consequences, such as: (i) re-writing orrestructuring mission-critical applications in order to avoid duplicatemodule names is expensive and risky because changing the name of a givenmodule means finding and changing all code segments that call thatmodule; and/or (ii) frequent and reliable update of an application isrequired to stay current with fixing bugs and with emerging usertechnologies (such as mobile versions of applications served by theapplication hosting system), but these updates lead to multiple versionsof an application.

Some embodiments of the present invention further recognize thefollowing potential problems with respect to customers adoptingsolutions to host multiple applications with “conflicting” (that is,duplicate) module names: (i) renaming the updated modules is timeconsuming; (ii) renaming the updated module carries the risk of notidentifying all the callers of the module concerned; (iii) in highlyperformance sensitive environments, changes to existing code is requiredwhen a directory is used to map the name (this is called “namingindirection”) rather than calling a module directly; (iv) in highlyperformance sensitive environments, imposed runtime overhead is requiredwhen naming indirection, rather than direct module calling, is used;and/or (v) hosting a new application version on a new CICS platform, inorder to avoid duplicate module naming, is expensive in terms of humanand/or computing resources.

In one embodiment of the present invention, a transaction server: (i)runs on a mainframe computer system; (ii) is implemented by“middleware;” (iii) is designed to support rapid, high-volume onlinetransaction processing; and (iv) includes dynamic libraries. Eachdynamic library identifies sets of data (herein called “datasets”) fromwhich modules are to be loaded as an application is run and modules arecalled in the running of the application. The dynamic libraries are notadded to the global search path, at least in cases where a given dynamiclibrary defined as part of an application. Instead, a given dynamiclibrary is added to a private search path. A dynamic library and itsassociated private search path may be shared by more than oneapplication (or more than one version of an application) so long as theapplications (or versions) do not use the same module nameinconsistently.

In this embodiment, when running a version of an application through thetransaction server, upon a module call by the application, the dynamiclibrary specified in the private search path of the application issearched before the global path.

This allows different applications (or versions) to define and loadmodules: (i) with the same name, but (ii) located in different datasets.Once in memory, a module can only “see” and “call” a module defined bythe same application. Certain modules can be marked as entry points andpromoted to the global namespace so applications can call each other.

Some embodiments of the present invention may include one, or more, ofthe following features, characteristics and/or advantages: (i) allowsmultiple versions of the application to be hosted on the sametransaction server (for example, CICS) platform without modifying modulenames; (ii) allows multiple versions of the application to be hosted onthe same transaction server platform without relying on namingindirection; (iii) application development remains unchanged; (iv)application deployment remains unchanged; and/or (v) significant costsavings can be realized if multiple versions of an application must bemade available, at the same time, to end users.

In some embodiments of the present invention, the transaction server'sdirectory is partitioned into both public and application private areas.Before performing a lookup of a called module, the transaction serverfirst retrieves the current application context from the task andsearches the application-private directory and dataset search pathbefore proceeding to the public one. The current application context isset when an entry point is: (i) invoked; (ii) stacked when a secondapplication entry point is invoked; and/or (iii) cleared when a publicmodule is called.

Some embodiments of the present invention concern or involve theconfiguration of the middleware so that existing software components(program load modules) can be used unchanged to represent differentversions of a service.

IV. Definitions

Present invention: should not be taken as an absolute indication thatthe subject matter described by the term “present invention” is coveredby either the claims as they are filed, or by the claims that mayeventually issue after patent prosecution; while the term “presentinvention” is used to help the reader to get a general feel for whichdisclosures herein are believed to potentially be new, thisunderstanding, as indicated by use of the term “present invention,” istentative and provisional and subject to change over the course ofpatent prosecution as relevant information is developed and as theclaims are potentially amended.

Embodiment: see definition of “present invention” above—similar cautionsapply to the term “embodiment.”

and/or: inclusive or; for example, A, B “and/or” C means that at leastone of A or B or C is true and applicable.

Computer: any device with significant data processing and/or machinereadable instruction reading capabilities including, but not limited to:desktop computers, mainframe computers, laptop computers,field-programmable gate array (FPGA) based devices, smart phones,personal digital assistants (PDAs), body-mounted or inserted computers,embedded device style computers, application-specific integrated circuit(ASIC) based devices.

1-5. (canceled)
 6. A computer program product for operating an onlinetransaction processing system to perform an application including afirst module call, the computer program product comprising a computerreadable storage medium having stored thereon: first programinstructions programmed to assign a dedicated search path to theapplication, where the search path specifies an ordered set oflocation(s) for searching for module code, the set of location(s)includes at least a first dynamic module library and the first dynamicmodule library is ahead of any other locations which may be included inthe dedicated search path; second program instructions programmed to runthe application through the transaction processing system; third programinstructions programmed to receive the first module call, from therunning of the application, specifying a requested module using arequested module name; and fourth program instructions programmed to, inresponse to the module call, locate the requested module based on therequested module name and the dedicated search path.
 7. The product ofclaim 6 wherein the transaction processing system is implemented bymiddleware running on a set of mainframe computer(s).
 8. The product ofclaim 6 wherein the storage medium has further stored thereon: fifthprogram instructions programmed to, in response to locating therequested module, perform the requested module.
 9. The product of claim6 wherein: the transaction processing system includes a plurality ofmodule libraries including the first dynamic module library; and therequested module name exists in more than one module library of theplurality of module libraries, but these multiple instances of therequested module name do not refer to the same module.
 10. The productof claim 9 wherein a given module name occurs no more than once in eachmodule library of the plurality of module libraries.
 11. A computersystem for operating an online transaction processing system to performan application including a first module call, the computer systemcomprising: a processor(s) set; and a computer readable storage medium;wherein: the processor set is structured, located, connected and/orprogrammed to run program instructions stored on the computer readablestorage medium; and the program instructions include: first programinstructions programmed to assign a dedicated search path to theapplication, where the search path specifies an ordered set oflocation(s) for searching for module code, the set of location(s)includes at least a first dynamic module library and the first dynamicmodule library is ahead of any other locations which may be included inthe dedicated search path; second program instructions programmed to runthe application through the transaction processing system; third programinstructions programmed to receive the first module call, from therunning of the application, specifying a requested module using arequested module name; and fourth program instructions programmed to, inresponse to the module call, locate the requested module based on therequested module name and the dedicated search path.
 12. The product ofclaim 11 wherein the transaction processing system is implemented bymiddleware running on a set of mainframe computer(s).
 13. The product ofclaim 11 wherein the storage medium has further stored thereon: fifthprogram instructions programmed to, in response to locating therequested module, perform the requested module.
 14. The system of claim11 wherein: the transaction processing system includes a plurality ofmodule libraries including the first dynamic module library; and therequested module name exists in more than one module library of theplurality of module libraries, but these multiple instances of therequested module name do not refer to the same module.
 15. The system ofclaim 14 wherein a given module name occurs no more than once in eachmodule library of the plurality of module libraries.